Dyestuffs of the dibenzanthrone series



Patented Feb. s, 1938 2,107,656

DYESTUFFS OF THE DIBENZANTHRONE SERIES Alexander J. Wuertz, Carrollville, and Ralph N. Lulek, Waukesha, Wis, assignors to E. I. du Pont de Nemours & Company, Wilmington, DeL, a corporation of Delaware No Drawing. Application October 19, 1936, Serial No. 106,366

2 Claims. (01. 260-61) This invention relates to the preparation of color) and heating to 60-70" C. for a short time. new dyestuffs of the dibenzanthrone series. From this solution it is precipitated in blue-black We have found that new and valuable gray flocks which are filtered off, washed free from and black vat dyestuffs of the dibenzanthrone acid and dried. 5 series can be prepared by reacting aminodi- The new dyestuff dyes and prints in reddish 5 benzanthrones with perchloromethylmercaptan. gray to black shades from a blue vat. These dyestuffs have the excellent fastness Example 2 properties characteristic of this class of compounds, with the added advantage that they dye parts aminodibenzanthrone (obtained by 10 directly in red-black shades as compared to the nitrating dibenzanthrone in sulfuric acid fol- 10 known aminodibenzanthrones of commerce lowed by reduction with alkali sulfide) are heated which must be developed on the fiber. These in 100 parts of. nitrobenzene to 140 C. 10 parts new compounds have also been found to have perchloromethylmercaptan are added and the good printing properties since they build up well, mass is heated to the boil for 1 hour. The dyeand they are therefore a valuable addition to the stuff is separated as in the foregoing example 15 field of dibenzanthrone colors. has similar properties.

According to our invention aminodibenzan- These new gray and black dyestuffs may be thrones are reacted with perchloromethylmeremployed as vat dyestuiis for dyeing or printing captan in an organic solvent at temperatures of or they may be converted to leuco esters by frome 120 C. to the boiling point of. the solvent methods employed for the solubilization of di- 20 employed. The exact chemical structure of benzanthrone dyestuffs and used for dyeing fiber these new compounds is not known, although in that form. they are believed to include a thiourea linkage. In the claims it should be understood that Any aminodibenzanthrone containing one or where new compounds are claimed, we mean to more amino groups may be employed; the shade include such compounds not only in substance, 25 of the ultimate dyestuir varying to some extent but also in whatever state they may exist when depending on the particular aminodibenzanapplied to material, dyed, printed or pigmented throne used. therewith.

The following examples are given to illustrate We claim: our invention. The parts used are by weight. 1. The products obtainable by reacting a pri- 30 mary aminodlbenzanthrone which contains no additional substituents with perchloromethyl- 10 parts aminodibenzanthrone (obtained by mercaptan, which are soluble in sulfuric acid nitrating dibenzanthrone in ortho-dichlorobenwith a violet color, and which dye cotton in gray zene with strong nitric acid followed by reducto black shades from blue vats. 35 tion with aluminum in sulfuric acid or with 2. In the process for preparing new gray to sodium sulfide in aqueous medium) are heated in black vat dyestuffs of the dibenzanthrone series, 100 parts nitrobenzene to 135-140 C. At this the step which comprises heating a primary temperature 10 parts perchloromethylmercaptan aminodibenzanthrone which contains no addi- 0 are added slowly. The temperature is then raised tional substituents with perchloromethylmergradually to the boil and maintained for 1 captan in an inert organic solvent, at temperahour. After cooling, the new dyestuff is sepatures above about 120 C. rated by filtration, washed and dried. It is a dark powder and may be purified by dissolving ALEXANDER J. WUERTZ. in sulfuric acid (in which it is soluble with violet RALPH N. LULEK. 45

Example 1 

